Semiconductor transistors formed on an integrated circuit are continuing to decrease is size. However, planar transistors which comprise a first current electrode laterally adjacent a channel region and a second current electrode laterally adjacent the channel region wherein the channel region separates the first and second current electrodes consume a significant amount of substrate space per transistor. Therefore, a significant amount of area that is consumed on an integrated circuit substrate is due to the planar or horizontal formation of transistors.
Today's integrated circuits are formed having millions of transistors and memory cells are formed such that millions of memory cells can be placed on a single integrated circuit. However, using planar transistors, the number of transistors that can be placed on a single integrated circuit is limited. It is now possible to form vertical transistors which generally take up less surface area than a planar transistor. However, vertical transistors are more difficult to form and may be difficult to contact/interconnect into the form of logic devices or memory cells in a small and acceptable area. Therefore, the need exists for new vertically formed trench transistors which have a smaller substrate footprint, are more manufacturable, and allow for the formation of more dense integrated circuits and memory cells.